Hi, I'm reposting this problem here as per suggestion on the OSS forums.
So here we go. I have this problem - the channel order gets messed up during the playback. Everything starts up just fine, but then at some time during the playback the channel order changes (i.e., center goes to subwoofer or front left, it looks like other channels shift accordingly). The seek or pause (which causes the player to close and reopen the dsp device) will always set the channel order back to normal. The problem is far more frequent when the system is under heavy load. When the system is otherwise idle, the problem happens quite rarely (once or twice during a 2 hour movie, sometimes not at all). However, when the system is loaded (either CPU or disk IO), the problem happens every few minutes, even though the playback is otherwise smooth. It seems that something is expecting a real-time response. I only use mplayer and OSS for playback, so it's gotta be either one of these causing problems. First I assumed it's mplayer, and, to verify that, tried a program similar to osstest, except with different sound on each channel. The playback was fine, regardless of the system load. So I posted a similar message to the mplayer's mailing list (http://article.gmane.org/gmane.comp.video.mplayer.user/58887), and have yet to receive any response... However, in the meantime, since my linux kernel was due for upgrade anyway, I decided to try ALSA drivers and see what happens. And guess what, the problem goes away. I used ALSA with OSS emulation, and mplayer with exactly the same setup (i.e., output through OSS). So now I'm not so sure anymore that the problem is with mplayer. It seems instead that this is either an outright OSS bug, or, more likely, the change in the OSS API semantics. The difference between OSS and ALSA is best seen when the system is heavily loaded. When using OSS, the channel order is pretty much random and the audio is choppy. But when using ALSA, the sound stays smooth all the way until the player starts dropping samples due to the sync problems (which requires a much higher system load), and the channel order never changes. System info: I tried OSS b1011, b1012, b1016, and b1050, VMIX disabled whenever possible. The machine is AMD64 quad-core, audio chip is CMI8788, I tried Debian and Solaris OS. Problem is always present to a varying degree. It is almost negligible on Linux when the machine is idle and VMIX is disabled. I would appreciate any suggestions on how to resolve this problem. Thanks in advance. _______________________________________________ oss-devel mailing list oss-devel@mailman.opensound.com http://mailman.opensound.com/mailman/listinfo/oss-devel
